diff options
Diffstat (limited to 'net/netfilter/nf_conntrack_proto.c')
| -rw-r--r-- | net/netfilter/nf_conntrack_proto.c | 523 |
1 files changed, 523 insertions, 0 deletions
diff --git a/net/netfilter/nf_conntrack_proto.c b/net/netfilter/nf_conntrack_proto.c new file mode 100644 index 000000000..b65d5864b --- /dev/null +++ b/net/netfilter/nf_conntrack_proto.c @@ -0,0 +1,523 @@ +/* L3/L4 protocol support for nf_conntrack. */ + +/* (C) 1999-2001 Paul `Rusty' Russell + * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> + * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org> + * (C) 2006-2012 Patrick McHardy <kaber@trash.net> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/types.h> +#include <linux/netfilter.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/mutex.h> +#include <linux/vmalloc.h> +#include <linux/stddef.h> +#include <linux/err.h> +#include <linux/percpu.h> +#include <linux/notifier.h> +#include <linux/kernel.h> +#include <linux/netdevice.h> + +#include <net/netfilter/nf_conntrack.h> +#include <net/netfilter/nf_conntrack_l3proto.h> +#include <net/netfilter/nf_conntrack_l4proto.h> +#include <net/netfilter/nf_conntrack_core.h> + +static struct nf_conntrack_l4proto __rcu **nf_ct_protos[PF_MAX] __read_mostly; +struct nf_conntrack_l3proto __rcu *nf_ct_l3protos[AF_MAX] __read_mostly; +EXPORT_SYMBOL_GPL(nf_ct_l3protos); + +static DEFINE_MUTEX(nf_ct_proto_mutex); + +#ifdef CONFIG_SYSCTL +static int +nf_ct_register_sysctl(struct net *net, + struct ctl_table_header **header, + const char *path, + struct ctl_table *table) +{ + if (*header == NULL) { + *header = register_net_sysctl(net, path, table); + if (*header == NULL) + return -ENOMEM; + } + + return 0; +} + +static void +nf_ct_unregister_sysctl(struct ctl_table_header **header, + struct ctl_table **table, + unsigned int users) +{ + if (users > 0) + return; + + unregister_net_sysctl_table(*header); + kfree(*table); + *header = NULL; + *table = NULL; +} +#endif + +struct nf_conntrack_l4proto * +__nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto) +{ + if (unlikely(l3proto >= AF_MAX || nf_ct_protos[l3proto] == NULL)) + return &nf_conntrack_l4proto_generic; + + return rcu_dereference(nf_ct_protos[l3proto][l4proto]); +} +EXPORT_SYMBOL_GPL(__nf_ct_l4proto_find); + +/* this is guaranteed to always return a valid protocol helper, since + * it falls back to generic_protocol */ +struct nf_conntrack_l3proto * +nf_ct_l3proto_find_get(u_int16_t l3proto) +{ + struct nf_conntrack_l3proto *p; + + rcu_read_lock(); + p = __nf_ct_l3proto_find(l3proto); + if (!try_module_get(p->me)) + p = &nf_conntrack_l3proto_generic; + rcu_read_unlock(); + + return p; +} +EXPORT_SYMBOL_GPL(nf_ct_l3proto_find_get); + +int +nf_ct_l3proto_try_module_get(unsigned short l3proto) +{ + int ret; + struct nf_conntrack_l3proto *p; + +retry: p = nf_ct_l3proto_find_get(l3proto); + if (p == &nf_conntrack_l3proto_generic) { + ret = request_module("nf_conntrack-%d", l3proto); + if (!ret) + goto retry; + + return -EPROTOTYPE; + } + + return 0; +} +EXPORT_SYMBOL_GPL(nf_ct_l3proto_try_module_get); + +void nf_ct_l3proto_module_put(unsigned short l3proto) +{ + struct nf_conntrack_l3proto *p; + + /* rcu_read_lock not necessary since the caller holds a reference, but + * taken anyways to avoid lockdep warnings in __nf_ct_l3proto_find() + */ + rcu_read_lock(); + p = __nf_ct_l3proto_find(l3proto); + module_put(p->me); + rcu_read_unlock(); +} +EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put); + +struct nf_conntrack_l4proto * +nf_ct_l4proto_find_get(u_int16_t l3num, u_int8_t l4num) +{ + struct nf_conntrack_l4proto *p; + + rcu_read_lock(); + p = __nf_ct_l4proto_find(l3num, l4num); + if (!try_module_get(p->me)) + p = &nf_conntrack_l4proto_generic; + rcu_read_unlock(); + + return p; +} +EXPORT_SYMBOL_GPL(nf_ct_l4proto_find_get); + +void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p) +{ + module_put(p->me); +} +EXPORT_SYMBOL_GPL(nf_ct_l4proto_put); + +static int kill_l3proto(struct nf_conn *i, void *data) +{ + return nf_ct_l3num(i) == ((struct nf_conntrack_l3proto *)data)->l3proto; +} + +static int kill_l4proto(struct nf_conn *i, void *data) +{ + struct nf_conntrack_l4proto *l4proto; + l4proto = (struct nf_conntrack_l4proto *)data; + return nf_ct_protonum(i) == l4proto->l4proto && + nf_ct_l3num(i) == l4proto->l3proto; +} + +static struct nf_ip_net *nf_ct_l3proto_net(struct net *net, + struct nf_conntrack_l3proto *l3proto) +{ + if (l3proto->l3proto == PF_INET) + return &net->ct.nf_ct_proto; + else + return NULL; +} + +static int nf_ct_l3proto_register_sysctl(struct net *net, + struct nf_conntrack_l3proto *l3proto) +{ + int err = 0; + struct nf_ip_net *in = nf_ct_l3proto_net(net, l3proto); + /* nf_conntrack_l3proto_ipv6 doesn't support sysctl */ + if (in == NULL) + return 0; + +#if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT) + if (in->ctl_table != NULL) { + err = nf_ct_register_sysctl(net, + &in->ctl_table_header, + l3proto->ctl_table_path, + in->ctl_table); + if (err < 0) { + kfree(in->ctl_table); + in->ctl_table = NULL; + } + } +#endif + return err; +} + +static void nf_ct_l3proto_unregister_sysctl(struct net *net, + struct nf_conntrack_l3proto *l3proto) +{ + struct nf_ip_net *in = nf_ct_l3proto_net(net, l3proto); + + if (in == NULL) + return; +#if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT) + if (in->ctl_table_header != NULL) + nf_ct_unregister_sysctl(&in->ctl_table_header, + &in->ctl_table, + 0); +#endif +} + +int nf_ct_l3proto_register(struct nf_conntrack_l3proto *proto) +{ + int ret = 0; + struct nf_conntrack_l3proto *old; + + if (proto->l3proto >= AF_MAX) + return -EBUSY; + + if (proto->tuple_to_nlattr && !proto->nlattr_tuple_size) + return -EINVAL; + + mutex_lock(&nf_ct_proto_mutex); + old = rcu_dereference_protected(nf_ct_l3protos[proto->l3proto], + lockdep_is_held(&nf_ct_proto_mutex)); + if (old != &nf_conntrack_l3proto_generic) { + ret = -EBUSY; + goto out_unlock; + } + + if (proto->nlattr_tuple_size) + proto->nla_size = 3 * proto->nlattr_tuple_size(); + + rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto); + +out_unlock: + mutex_unlock(&nf_ct_proto_mutex); + return ret; + +} +EXPORT_SYMBOL_GPL(nf_ct_l3proto_register); + +int nf_ct_l3proto_pernet_register(struct net *net, + struct nf_conntrack_l3proto *proto) +{ + int ret = 0; + + if (proto->init_net) { + ret = proto->init_net(net); + if (ret < 0) + return ret; + } + + return nf_ct_l3proto_register_sysctl(net, proto); +} +EXPORT_SYMBOL_GPL(nf_ct_l3proto_pernet_register); + +void nf_ct_l3proto_unregister(struct nf_conntrack_l3proto *proto) +{ + BUG_ON(proto->l3proto >= AF_MAX); + + mutex_lock(&nf_ct_proto_mutex); + BUG_ON(rcu_dereference_protected(nf_ct_l3protos[proto->l3proto], + lockdep_is_held(&nf_ct_proto_mutex) + ) != proto); + rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], + &nf_conntrack_l3proto_generic); + mutex_unlock(&nf_ct_proto_mutex); + + synchronize_rcu(); +} +EXPORT_SYMBOL_GPL(nf_ct_l3proto_unregister); + +void nf_ct_l3proto_pernet_unregister(struct net *net, + struct nf_conntrack_l3proto *proto) +{ + nf_ct_l3proto_unregister_sysctl(net, proto); + + /* Remove all contrack entries for this protocol */ + nf_ct_iterate_cleanup(net, kill_l3proto, proto, 0, 0); +} +EXPORT_SYMBOL_GPL(nf_ct_l3proto_pernet_unregister); + +static struct nf_proto_net *nf_ct_l4proto_net(struct net *net, + struct nf_conntrack_l4proto *l4proto) +{ + if (l4proto->get_net_proto) { + /* statically built-in protocols use static per-net */ + return l4proto->get_net_proto(net); + } else if (l4proto->net_id) { + /* ... and loadable protocols use dynamic per-net */ + return net_generic(net, *l4proto->net_id); + } + return NULL; +} + +static +int nf_ct_l4proto_register_sysctl(struct net *net, + struct nf_proto_net *pn, + struct nf_conntrack_l4proto *l4proto) +{ + int err = 0; + +#ifdef CONFIG_SYSCTL + if (pn->ctl_table != NULL) { + err = nf_ct_register_sysctl(net, + &pn->ctl_table_header, + "net/netfilter", + pn->ctl_table); + if (err < 0) { + if (!pn->users) { + kfree(pn->ctl_table); + pn->ctl_table = NULL; + } + } + } +#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT + if (l4proto->l3proto != AF_INET6 && pn->ctl_compat_table != NULL) { + if (err < 0) { + nf_ct_kfree_compat_sysctl_table(pn); + goto out; + } + err = nf_ct_register_sysctl(net, + &pn->ctl_compat_header, + "net/ipv4/netfilter", + pn->ctl_compat_table); + if (err == 0) + goto out; + + nf_ct_kfree_compat_sysctl_table(pn); + nf_ct_unregister_sysctl(&pn->ctl_table_header, + &pn->ctl_table, + pn->users); + } +out: +#endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */ +#endif /* CONFIG_SYSCTL */ + return err; +} + +static +void nf_ct_l4proto_unregister_sysctl(struct net *net, + struct nf_proto_net *pn, + struct nf_conntrack_l4proto *l4proto) +{ +#ifdef CONFIG_SYSCTL + if (pn->ctl_table_header != NULL) + nf_ct_unregister_sysctl(&pn->ctl_table_header, + &pn->ctl_table, + pn->users); + +#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT + if (l4proto->l3proto != AF_INET6 && pn->ctl_compat_header != NULL) + nf_ct_unregister_sysctl(&pn->ctl_compat_header, + &pn->ctl_compat_table, + 0); +#endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */ +#endif /* CONFIG_SYSCTL */ +} + +/* FIXME: Allow NULL functions and sub in pointers to generic for + them. --RR */ +int nf_ct_l4proto_register(struct nf_conntrack_l4proto *l4proto) +{ + int ret = 0; + + if (l4proto->l3proto >= PF_MAX) + return -EBUSY; + + if ((l4proto->to_nlattr && !l4proto->nlattr_size) + || (l4proto->tuple_to_nlattr && !l4proto->nlattr_tuple_size)) + return -EINVAL; + + mutex_lock(&nf_ct_proto_mutex); + if (!nf_ct_protos[l4proto->l3proto]) { + /* l3proto may be loaded latter. */ + struct nf_conntrack_l4proto __rcu **proto_array; + int i; + + proto_array = kmalloc(MAX_NF_CT_PROTO * + sizeof(struct nf_conntrack_l4proto *), + GFP_KERNEL); + if (proto_array == NULL) { + ret = -ENOMEM; + goto out_unlock; + } + + for (i = 0; i < MAX_NF_CT_PROTO; i++) + RCU_INIT_POINTER(proto_array[i], &nf_conntrack_l4proto_generic); + + /* Before making proto_array visible to lockless readers, + * we must make sure its content is committed to memory. + */ + smp_wmb(); + + nf_ct_protos[l4proto->l3proto] = proto_array; + } else if (rcu_dereference_protected( + nf_ct_protos[l4proto->l3proto][l4proto->l4proto], + lockdep_is_held(&nf_ct_proto_mutex) + ) != &nf_conntrack_l4proto_generic) { + ret = -EBUSY; + goto out_unlock; + } + + l4proto->nla_size = 0; + if (l4proto->nlattr_size) + l4proto->nla_size += l4proto->nlattr_size(); + if (l4proto->nlattr_tuple_size) + l4proto->nla_size += 3 * l4proto->nlattr_tuple_size(); + + rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto], + l4proto); +out_unlock: + mutex_unlock(&nf_ct_proto_mutex); + return ret; +} +EXPORT_SYMBOL_GPL(nf_ct_l4proto_register); + +int nf_ct_l4proto_pernet_register(struct net *net, + struct nf_conntrack_l4proto *l4proto) +{ + int ret = 0; + struct nf_proto_net *pn = NULL; + + if (l4proto->init_net) { + ret = l4proto->init_net(net, l4proto->l3proto); + if (ret < 0) + goto out; + } + + pn = nf_ct_l4proto_net(net, l4proto); + if (pn == NULL) + goto out; + + ret = nf_ct_l4proto_register_sysctl(net, pn, l4proto); + if (ret < 0) + goto out; + + pn->users++; +out: + return ret; +} +EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_register); + +void nf_ct_l4proto_unregister(struct nf_conntrack_l4proto *l4proto) +{ + BUG_ON(l4proto->l3proto >= PF_MAX); + + mutex_lock(&nf_ct_proto_mutex); + BUG_ON(rcu_dereference_protected( + nf_ct_protos[l4proto->l3proto][l4proto->l4proto], + lockdep_is_held(&nf_ct_proto_mutex) + ) != l4proto); + rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto], + &nf_conntrack_l4proto_generic); + mutex_unlock(&nf_ct_proto_mutex); + + synchronize_rcu(); +} +EXPORT_SYMBOL_GPL(nf_ct_l4proto_unregister); + +void nf_ct_l4proto_pernet_unregister(struct net *net, + struct nf_conntrack_l4proto *l4proto) +{ + struct nf_proto_net *pn = NULL; + + pn = nf_ct_l4proto_net(net, l4proto); + if (pn == NULL) + return; + + pn->users--; + nf_ct_l4proto_unregister_sysctl(net, pn, l4proto); + + /* Remove all contrack entries for this protocol */ + nf_ct_iterate_cleanup(net, kill_l4proto, l4proto, 0, 0); +} +EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_unregister); + +int nf_conntrack_proto_pernet_init(struct net *net) +{ + int err; + struct nf_proto_net *pn = nf_ct_l4proto_net(net, + &nf_conntrack_l4proto_generic); + + err = nf_conntrack_l4proto_generic.init_net(net, + nf_conntrack_l4proto_generic.l3proto); + if (err < 0) + return err; + err = nf_ct_l4proto_register_sysctl(net, + pn, + &nf_conntrack_l4proto_generic); + if (err < 0) + return err; + + pn->users++; + return 0; +} + +void nf_conntrack_proto_pernet_fini(struct net *net) +{ + struct nf_proto_net *pn = nf_ct_l4proto_net(net, + &nf_conntrack_l4proto_generic); + + pn->users--; + nf_ct_l4proto_unregister_sysctl(net, + pn, + &nf_conntrack_l4proto_generic); +} + +int nf_conntrack_proto_init(void) +{ + unsigned int i; + for (i = 0; i < AF_MAX; i++) + rcu_assign_pointer(nf_ct_l3protos[i], + &nf_conntrack_l3proto_generic); + return 0; +} + +void nf_conntrack_proto_fini(void) +{ + unsigned int i; + /* free l3proto protocol tables */ + for (i = 0; i < PF_MAX; i++) + kfree(nf_ct_protos[i]); +} |